Over the past several years in particular, there has been increasing concern about the level of pollution in the atmosphere, as well as attempts of various kinds to remediate various pollutant conditions. In the lower troposphere portion of the atmosphere, 0-2 km above the earth's surface, the primary pollutants are in the form of smog or smog-like particulates, but also include many other harmful chemicals. The smog often is in the form of a dense layer, trapped by a temperature inversion. The smog layer then traps other pollutants, increasing the pollution problem. This condition poses well-known health risks.
One of the most significant current issues in atmospheric pollution concerns the ozone layer, which is located in the stratosphere region of the atmosphere, 20 to 50 km above the earth's surface. The ozone layer is known to be of critical importance to the ecology of the earth. Unfortunately, the ozone layer has already been depleted to a significant extent, to the point where the existence of an ozone "hole" has been verified over the Antarctic region.
It has been discovered that ozone is destroyed by a reaction with chlorine atoms, with one chlorine atom apparently capable of catalytically reacting with and destroying approximately 500,000 ozone molecules. The presence of chlorine in the stratosphere is produced by both natural and anthropogenic sources, among which is the disassociation of chlorofluorocarbons (CFCs) by means of ultraviolet radiation in that region of the atmosphere.
Chlorofluorocarbons are produced on earth as a byproduct of various industrial processes, and then slowly migrate through the troposphere up into the stratospheric region of the atmosphere, where the ozone layer is located. This migration is often quite slow and will typically take many years, even decades, to complete. The disadvantage of this slow migration is that while a decrease in the production of chlorofluorocarbons on earth will eventually result in a decrease in the amount of chlorine in the stratosphere and a corresponding decrease in the destruction of ozone, there remains a substantial amount of CFCs already present in the atmosphere which will continue to migrate over quite a long period of time into the stratosphere, resulting in the continuing depletion of the ozone layer.
With respect to the problem of smog, there have been a number of suggestions for remediating lower troposphere pollutants. One example of such a system is U.S. Pat. No. 5,147,429 to Bartholomew et al. However, this is a complex and expensive mechanical device involving a number of different conventional elements, including scrubbers and filtration machines. Further, such devices typically have a relatively small capacity compared to the extent of lower troposphere pollution and furthermore require a substantial amount of power, both of which are significant disadvantages.
With respect to the ozone layer, certain measures designed to mitigate the depletion of the ozone layer also have been suggested, in addition to the previously noted suggestions of significantly decreasing production of chlorofluorocarbons.
One possibility involves the conversion of chlorine atoms into negative ions so as to reduce their reactivity. A. Y. Wong, R. Wuerker, J. Sabutis, and R. Suchannek, C. D. Hendricks and P. Gottlieb, "Ion Dynamics and Ozone," Proceedings of the International Workshop on Controlled Active Global Experiments, held in Varenna, Italy, September 1990. Another possibility concerns the use of chemical hydrocarbons to scavenge the chlorine radical. R. J. Cicerone, S. Elliot and R. P. Turco, Science 254, 1191 (1991). However, no suggestions have been made with respect to an actual apparatus or method for actually implementing such theoretical suggestions in the atmosphere.
Hence, there remains a significant need for a large scale means for remediation of the chlorofluorocarbons which result in ozone depletion, as well as a need for a practical, large-scale means for reducing pollution in the lower troposphere.
In addition to the above-noted issues concerning atmospheric remediation, regional and global telecommunication needs present challenging problems which may be assisted by large-scale stratospheric systems similar to those described herein